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Landau-Kleffner Syndrome (LKS), also known as Acquired Epileptic Aphasia, is a rare neurological condition characterized by sudden or gradual aphasia and epileptiform EEG abnormalities in previously healthy children. The historical trajectory of LKS reflects a rich collaboration between neurology and speech pathology.

Discovery and Initial Observations

  • Landau-Kleffner syndrome was first described in 1957 by neurologist William M. Landau and speech pathologist Frank R. Kleffner.
    • William Milton Landau (October 10, 1924[1] – November 2, 2017) was an American neurologist who was a professor of neurology at the Washington University School of Medicine in St. Louis, Missouri. William Landau died November 2, 2017, of natural causes at his home in University City, Missouri. He was 93.
    • Frank R. Kleffner (October 10, 1925 – June 12, 2015) was an American pathologist who was a professor at Washington University in St. Louis, noted for his contributions in the fields of speech and language pathology and hearing.
  • Both practitioners initially observed six children with acquired aphasia and concurrent convulsive disorders at the Central Institute for the Deaf.
  • They meticulously documented the effects of pharmacological and speech therapies, noting significant EEG abnormalities. Their groundbreaking study, “Syndrome of Acquired Aphasia With Convulsive Disorder in Children,” linked EEG improvement directly with recovery in language skills.
  • This seminal paper, published in 1957, sparked considerable attention and led to approximately 160 additional documented diagnoses between 1957 and 1990.

Frank KleffnerFrank Kleffner

Follow-up and Subsequent Research

  • In 1980, Landau collaborated with pediatric neurologist John F. Mantovani on a follow-up study involving nine patients, including the original six described in 1957. This study assessed patient outcomes 10 to 28 years post-onset, underscoring the syndrome’s persistence and complexity.
  • William M. Landau expressed concern decades later, emphasizing his frustration over limited progress: “We haven’t learned much at all. We know nothing about cause yet.” He advocated for a structured, multi-institutional approach to research potential etiologies and treatments comprehensively.

landauWilliam M. Landau

Clinical Insights and Challenges

  • According to Sharon Willig, associate director of speech-language pathology at ASHA, “The hallmark feature of Landau-Kleffner syndrome is a loss of receptive and expressive speech and language skills.” Such profound impairment often results in affected children becoming progressively mute, leading to frequent misdiagnosis as developmental delay or hearing impairment.
  • LKS typically exhibits spontaneous improvement around age 15, likely driven by cerebral maturation and hormonal changes. Nevertheless, many children endure lasting neurological impairments, varying from minimal deficits to profound disability, even after EEG normalization.
  • Parents and clinicians describe this uncertain trajectory as profoundly challenging—“the hardest waiting game they'll ever have to play.”

Personal Perspectives from the Syndrome’s Namesakes

Frank R. Kleffner, reflecting modestly on the condition named after him, expressed humility about its significance. Retired since 1991, he humorously described LKS as “a badge of eponymic ignorance,” lamenting persistent gaps in understanding despite decades of research.

  • In a notable anecdote, Kleffner recalls initially doubting Landau’s announcement of their eponymous syndrome appearing in medical literature, illustrating early disbelief at the emerging recognition.

Current Perspectives and Ongoing Controversies

  • The understanding of LKS has evolved significantly. The EEG findings typical of LKS now appear in various disorders, complicating clear diagnostic boundaries.
  • The brain of children with LKS demonstrates inherent susceptibility, possibly related to abnormal neural circuitry impairing language and memory imprinting during sleep, interfering with normal cognitive development and synaptic pruning.
  • There is ongoing controversy regarding classification: many clinicians use “LKS” loosely for cases involving language regression and EEG abnormalities, overlapping significantly with autism spectrum disorders and complicating precise diagnosis.
  • Kleffner himself acknowledges this diagnostic confusion, expressing concern that genuine LKS cases may be overshadowed by broader diagnostic criteria and clinical variability.

Future Directions

  • The fifty-plus years since the initial description of LKS have underscored both progress and significant gaps in knowledge. Researchers stress the urgent need for standardized, multicentric studies to elucidate causes, refine diagnostic criteria, and develop effective interventions.
  • As Landau himself advocated, modern research must prioritize collaborative frameworks that leverage advanced imaging techniques, genetic analyses, and longitudinal studies to gain deeper insights into this enigmatic syndrome.

Cover Image: Mercury and Argus - Camillo Procaccini (Italian, 1546-1629). Mercury uses his words and stories strategically to lull the watchful Argus—symbolizing the power of speech and its persuasive qualities.